About this replacement
Globus Elite SII / Genesy S2 — 4.8V Ni-MH Replacement Battery (FKG3870)
This is a 4.8V, 700mAh Ni-MH replacement battery for the Globus Elite SII, Genesy S2, Duo Tens, and A3R electrical stimulators. It uses OEM part number FKG3870 and slots directly into the battery compartment of these portable therapy units. Capacity is 700mAh (3.36Wh), matching the original cell specification.
- Elite SII, Genesy S2, Duo Tens, A3R compatibility: These four units share the same 4.8V cell format, connector pinout, and BMS handshake protocol — the same physical pack services all four without modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge on the Elite SII platform. The BMS completed its verification sequence, accepted the cell chemistry, and reported accurate state-of-charge after one full cycle.
- Post-swap self-test protocol: After fitting this battery, let the device complete its full power-on self-test without switching it off mid-sequence. Interrupting startup causes a false battery fault that persists until the next full reboot — this is a BMS verification step, not a battery fault.
Device not completing boot sequence on new battery
The Elite SII runs a BMS learn cycle on first use with a new cell. If the device stalls mid-boot or displays an error, the BMS has not yet mapped the new cell's internal resistance profile. This is normal for Ni-MH chemistry on first installation. Power the unit off fully, then restart and allow the boot sequence to complete uninterrupted. One full charge-discharge cycle clears the learn cycle and resolves the fault.
Charge indicator not reaching 100% on the first charge
On the first charge after installation, the onboard charge IC applies a conservative current limit to the new cell. This is expected behaviour — the controller has not yet calibrated to the replacement cell's capacity curve. The indicator will plateau below full and may show 80–90% even after a complete charge cycle. Run one full discharge to the device's automatic cutoff, then charge again to full; the charge IC recalibrates and the indicator reads correctly from the second cycle onward.